Sketched Game: Dark Void and game length

Sorry this is late, I actually finished the game last week(and really late if you consider the game came out in 2010), and I've been a little sick *cough cough* but I wanted to talk about Dark Void.  

You play William Grey in the midst of WWII when you're sucked into a portal and go through another dimension filled with robots and tribes people. Pretty soon you find a jetpack and some guns and proceed to shoot robot aliens in the face to save WWII or something.